Reverse brake



Aug. 17, 1948. F, 1| DAVIS'Er AL 2,447,167

REVERSE BRAKE Fi1ed June 11 1945 401ml d@ I INVENTORS 27 iff/2f 29 Patented Aug. 17, 194s REVERSE BRAKE Francis H. Davis, Ovid C. Emerson, and Percy A. Newman, La Fayette, Ind., assignors to Ross Gear & Tool Company, La Fayette, Ind., a corporation of Indiana Application June 11, 1945, serial No. 598,756

3 claims. (01.192-8) Our invention is concerned with a reverse brake for use in association with coaxial drivingrrand driven members to prevent rotation of saidV two members under the iniiuence of a torque applied to the driven member while permitting their free rotation when atorque is applied to the driving member. It is the object of our invention to produce a reverse brake which c-an be simply and economically manufactured and which will be adaptable for use in a wide variety of situations. A further object of our invention is to provide a reverse brake which while effective for its intended purpose in preventing rotation under the influence of a torque applied to the driven member will not seize and may be quickly released When a torque is applied to the driving member.

In ycarrying out our invention we provide the driving and driven members with axially overlapping, opposed elements disposed in a stationary sleeve. Within this sleeve We provide an arcuate brake member having at its ends shoes adapted to bear frictionally against the inner surface of the sleeve, The inner faces of such shoes are inclined relative to each other to co-operate with a wedge member which extends generally dianietrically of the sleeve and is loosely received between the two opposed elements. Those faces of the two elements which are presented toward the wedge are soshaped that rotation of the driven member in either direction will move the wedge perpendicularly of itself to expand the brake member while rotation of the driving 'member will move the wedge in the opposite direction to permit the brake member to contract.

The accompanying drawings illustrate our invention: Fig. 1 is an axial section through a reverse brake embodying our invention; Fig. 2 is a transverse section on the line 2-2 of Fig. 1 show- Y ing the parts of the 4brake in their neutral positions; and Fig. 3 isv a View similar to Fig. 2 illustrating the positions of the parts when the brake is locked.

The device illustrated in the drawing embodies a housing I0 provided with an extension II coaxial with a driven member in the form of a helical cam I2. The cam I2 is rotatably supported in the housing I0 through the medium of suitable bearings including the kanti-friction bearing I3 and is provided with a coaxial pilot I4 rigidly connected with the cam through the medium of an eccentric bridge I5. The pilot I4 is rotatably received in a sleeve I5 which is rigidly connected, as by means of a transverse pin I'I, with a manually operable driving shaft I8, To prevent relawill be clear from Figs. 2 and 3.

tive axial movementof the sleeve I6 and pilot I4while permitting their'relative rotation, the latter 4may be provided with an vannular groove I9 for the receipt of an eccentric pin 20 in the sleeve. The sleeve Y I6 is provided with an extensionfZI which projects into axially overlapping relation with the bridge I5 and is spaced therefromf Y Within the housing-extension I I we provide `a sleeve 25, preferably hardened and ground. The

sleeve 25 is prevented from rotating inv the housy ing by means of a plate 26 which is disposed over the end of the housing-extension I I and provided withv two inwardly projecting ears 2l receivedin notches in theL sleeve. A cap 28 overlies the plate 26; and the cap and plate Vare held in position by screws (not shown) which pass through them into holes 29 in the extension Il, 'A lubricantV sealing ring 30 is desirably provided between the cap 28 and the sleeve I6.

VWithin the sleeve 25 and in the plane of the overlapping bridge I5 and extension 2I there is a brake member 35, Such brake member is arcuate in shape, desirably of somewhat more than in total circumferential extent, and is provided at its ends With shoes 36 the exterior surfaces of which conform in curvature to the inner surface of the sleeve 25. VDesirably, the outer surface of the brake member 35 is relieved, as indicated at 3'I, between the shoes 36 and a third or intermediate shoe 38 adapted t0 bear against the inner surface of the sleeve. Y Y

The inner surfaces of the Vshoes 35 are inclined with respect to each other, converging toward the extension ZI; and between them there is located a wedge member 40 whose end faces are tapered complementarily to the inner faces of the shoes 36.

lThe wedge memberv extends generally diametrically `of the sleeve 25 between the bridge l5 and the extension 2 I and is somewhat narrower than the space between the extension and bridge, as Those faces of the bridge I5 and extension 2l which are presented toward the wedge are so shaped that upon rotation relative to the wedge they will engage it ybetween its ends and its middle.

If desired, those ends of the shoes 36 adjacent the extension 2I may be provided with shoulders 4I positioned to be engaged respectivelyvby the ends of th'e extension 2I as the latter rotates.

The parts of the device are illustrated in their neutral positions in Fig. 2. From this figure, it will be clear that either the bridge I5 or the extension 2| can rotate to a limited extent while the other of such elements remains stationary.

3 If the bridge l5 is rotated by a torque transmitted to it through the cam l2 it will engage the wedge di), as indicated in Fig. 3, and force it downwardly causing it to urge the shoes 36 outwardly into rm gripping engagement with the inner surface of the sleeve 25. The lost-motion between the bridge l5 :and the extension 2l permits this gripping engagement to occur beforev the wedge engages the extension 2! to transmit torque to the sleeve l and shaft i3. Irrespective of the direction in which the bridge I6 rotates from its neutral position shown in Fig. 2 it will engage the wedge B and cause it to expand the brake member and prevent further rotation; If, on the other hand, the shaft i8 is rotated by the operator, one end of the extension 2l will engage the wedge and lift it upwardly, thus relieving any expanding eiort previously exerted by the wedge on the brake member. As rota'- tion of the shaft i8 is continued, torque will be transmitted from the extension 2l through the wedge il to the bridge l5, and thereafter the cam l2 will be rotated with the shaft ld. In this rotation the action of the wedge on the brake member will cause it to rotate with the driving shaft i8 and cam l2; but should the wedge fail to drive the brake member'in this rotation, one of the shoulders ll Ywill be engaged by the adjacent end of the extension 2l to cause the brake member to be rotated positively.

We claim as our invention:

1. In combination, a stationary member having a circular bore, rotatable driving and driven members coaxial with said bore, said driving and driven members being provided with axially overlapping extensions arranged in opposed relationship with'in said bore, an arcuate brake member disposed in said bore, 'an actuator disposed between the ends of said brake member, said actuator being located between said extensions and providing a lost-motion connection between them, said actuator having end faces converging toward each other away Yfrom the extension on said Idriven member, said brake member being provided interiorly with faces ycomplementary to and respectively engaged by the end faces of said 'actuator and also with shoulders engageable by one of said extensions to limit the extent to which such extension can rotate relatively to the brake member.

2. In combination, a stationary member having a central bore, rotatable driving and driven members coaxial with said bore, an actuator extending generally diametrically of said bore and having its ends spaced from the bore-surface, an arcuate brake member having end portions disposed respectively between the ends of said actuator and the bore-surface and a resilient intermediate portion interconnecting said end portions, said driving and driven members being provided with extensions disposed respectively on opposite sides of said actuator and spaced therefrom whereby said actuator will provide a lost-motion connection between the extensions, said actuator engaging the end portions of said brake member over surfaces which converge toward each' other away from the extension on said driven member and which are disposed adjacent opposite ends of a diameter of said bore.

3. In combination, a stationary member having a central bore, an arcuate brake member disposed in said bore, and an actuator having a portion disposed between the ends of said brake member and engaging such brake-member ends over converging surfaces, said driven member being provided with an abutment extending axially into overlapping relation with said actuator and engageable therewith upon rotation of 4the driven member to move said actuator radially in the direction in which said surfaces converge, said driving member being provid-ed with an abutment extending axially into overlapping relation with said actuator and engageable therewith upon rotation of the driving member to move said actuator radially in the opposite direction, the points at which the abutment on said driven member engages said actuator being located between the planes of said converging surfaces.

FRANCIS H. DAVIS. OVID C. EMERSON. PERCY A. NEWMAN.

REFERENCES CITED The following references are ofrecord in the file of this patent:

n UNITED STATES PATENTS Number 

